1. Field of the Invention
This invention relates to the treatment of effluents containing inks, particularly emulsion inks, used in printing processes in printing works and in all other industries such as, e.g., paper, cardboard and similar factories.
2. Background of the Prior Art
In the industries involved in the transformation of paper or cardboard, the effluents to be treated can contain various pollutants and in particular emulsion inks, particularly when the industrial installation uses a flexographic printing process. They may also contain adhesive residues, e.g., based on starch.
In order to treat these effluents, numerous processes have already been proposed. They generally consist of separating by different methods the polluting agents from the water containing them, in order to obtain on one side polluting sludge and on the other the clarified effluent. The polluting sludge obtained is then eliminated, generally by incineration.
Thus, a flocculation-based separating process has been proposed, which is followed by the static decanting of the effluents. However, the sludge obtained through the performance of this process is not very dense, so that the volume to be destroyed is considerable and incineration costs are high.
In order to obtain more compact sludge, it has already been proposed to use a filter press making it possible to pass from a dryness of 2 to 3% to a dryness of approximately 30%. However, one of the disadvantages of the filter press is that its flow rate is variable being linked with the clogging of the cloths, which can occur rapidly.
The filter press also requires manpower for monitoring it, particularly at the time of removing the cake.
In addition, an ultra-filtration separating process has been proposed. However, this is an onerous process and the problem of membrane or cloth clogging again occurs. This can also be irreversible in the case of removal of products such as hydrocarbons, oils and special adhesive.